/*
 * Copyright 1999-2011 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.druid.support.json;

import com.alibaba.druid.util.Utils;

import javax.management.openmbean.CompositeData;
import javax.management.openmbean.TabularData;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Map;

public class JSONWriter {

	private StringBuilder out;

	public JSONWriter() {
		this.out = new StringBuilder();
	}

	public void writeArrayStart() {
		write('[');
	}

	public void writeComma() {
		write(',');
	}

	public void writeArrayEnd() {
		write(']');
	}

	public void writeNull() {
		write("null");
	}

	@SuppressWarnings({ "unchecked", "rawtypes" })
	public void writeObject(Object o) {
		if (o == null) {
			writeNull();
			return;
		}

		if (o instanceof String) {
			writeString((String) o);
			return;
		}

		if (o instanceof Number) {
			write(o.toString());
			return;
		}

		if (o instanceof Boolean) {
			write(o.toString());
			return;
		}

		if (o instanceof Date) {
			writeDate((Date) o);
			return;
		}

		if (o instanceof Collection) {
			writeArray((Collection) o);
			return;
		}

		if (o instanceof Throwable) {
			writeError((Throwable) o);
			return;
		}

		if (o instanceof int[]) {
			int[] array = (int[]) o;
			write('[');
			for (int i = 0; i < array.length; ++i) {
				if (i != 0) {
					write(',');
				}
				write(array[i]);
			}
			write(']');
			return;
		}

		if (o instanceof long[]) {
			long[] array = (long[]) o;
			write('[');
			for (int i = 0; i < array.length; ++i) {
				if (i != 0) {
					write(',');
				}
				write(array[i]);
			}
			write(']');
			return;
		}

		if (o instanceof TabularData) {
			writeTabularData((TabularData) o);
			return;
		}

		if (o instanceof CompositeData) {
			writeCompositeData((CompositeData) o);
			return;
		}

		if (o instanceof Map) {
			writeMap((Map) o);
			return;
		}

		throw new IllegalArgumentException("not support type : " + o.getClass());
	}

	public void writeDate(Date date) {
		if (date == null) {
			writeNull();
			return;
		}
		// SimpleDataFormat is not thread-safe, we need to make it local.
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		writeString(dateFormat.format(date));
	}

	public void writeError(Throwable error) {
		if (error == null) {
			writeNull();
			return;
		}

		write("{\"Class\":");
		writeString(error.getClass().getName());
		write(",\"Message\":");
		writeString(error.getMessage());
		write(",\"StackTrace\":");
		writeString(Utils.getStackTrace(error));
		write('}');
	}

	public void writeArray(Object[] array) {
		if (array == null) {
			writeNull();
			return;
		}

		write('[');

		for (int i = 0; i < array.length; ++i) {
			if (i != 0) {
				write(',');
			}
			writeObject(array[i]);
		}

		write(']');
	}

	public void writeArray(Collection<Object> list) {
		if (list == null) {
			writeNull();
			return;
		}

		int entryIndex = 0;
		write('[');

		for (Object entry : list) {
			if (entryIndex != 0) {
				write(',');
			}
			writeObject(entry);
			entryIndex++;
		}

		write(']');
	}

	public void writeString(String text) {
		if (text == null) {
			writeNull();
			return;
		}

		write('"');
		for (int i = 0; i < text.length(); ++i) {
			char c = text.charAt(i);
			if (c == '"') {
				write("\\\"");
			} else if (c == '\n') {
				write("\\n");
			} else if (c == '\r') {
				write("\\r");
			} else if (c == '\\') {
				write("\\\\");
			} else if (c == '\t') {
				write("\\t");
			} else if (c < 16) {
				write("\\u000");
				write(Integer.toHexString(c));
			} else if (c < 32) {
				write("\\u00");
				write(Integer.toHexString(c));
			} else if (c >= 0x7f && c <= 0xA0) {
				write("\\u00");
				write(Integer.toHexString(c));
			} else {
				write(c);
			}
		}
		write('"');
	}

	public void writeTabularData(TabularData tabularData) {
		if (tabularData == null) {
			writeNull();
			return;
		}

		int entryIndex = 0;
		write('[');

		for (Object item : tabularData.values()) {
			if (entryIndex != 0) {
				write(',');
			}
			CompositeData row = (CompositeData) item;
			writeCompositeData(row);

			entryIndex++;
		}
		write(']');
	}

	public void writeCompositeData(CompositeData compositeData) {
		if (compositeData == null) {
			writeNull();
			return;
		}

		int entryIndex = 0;
		write('{');

		for (Object key : compositeData.getCompositeType().keySet()) {
			if (entryIndex != 0) {
				write(',');
			}
			writeString((String) key);
			write(':');
			Object value = compositeData.get((String) key);
			writeObject(value);
			entryIndex++;
		}

		write('}');
	}

	public void writeMap(Map<String, Object> map) {
		if (map == null) {
			writeNull();
			return;
		}

		int entryIndex = 0;
		write('{');
		for (Map.Entry<String, Object> entry : map.entrySet()) {
			if (entryIndex != 0) {
				write(',');
			}

			writeString(entry.getKey());
			write(':');
			writeObject(entry.getValue());

			entryIndex++;
		}

		write('}');
	}

	protected void write(String text) {
		out.append(text);
	}

	protected void write(char c) {
		out.append(c);
	}

	protected void write(int c) {
		out.append(c);
	}

	protected void write(long c) {
		out.append(c);
	}

	public String toString() {
		return out.toString();
	}
}
